Bieber plays a prank on Swift

Justin Bieber has turned practical joker, as he Punk'd country singer Taylor Swift.

The Never Say Never star, one of the guest presenters on the new series of the MTV show, was seen comforting a visibly shocked Taylor after she is worried that she may have ruined a couple's wedding, when a boat catches fire, in the clip for the trailer to promote the new season.

Justin tricks Taylor into playing with some fireworks, when a flame 'ignites' the boat and sets it in flames.

He is heard saying: "I think we should start with Taylor, she's the sweetest girl ever", before she appears on screen looking concerned about the fire, saying: "This is completely not OK!"

Justin is the first celebrity host to present the hidden camera show, which is back on screens from March 29 after a five year hiatus. He has taken over from previous host Ashton Kutcher, who continues to act as the show's producer.